Adams J F, McEwan F
J Clin Pathol. 1971 Feb;24(1):15-7. doi: 10.1136/jcp.24.1.15.
Coenzyme B(12) and methylcobalamin in water are less active in promoting growth of Euglena gracilis Z strain than the same concentrations of cyanocobalamin and hydroxocobalamin which are equally active. When bound to human serum or human liver homogenate, however, the activities of these four cobalamins do not differ significantly with one exception. The results suggest that the Euglena assay using cyanocobalamin standards is not satisfactory for quantitation of coenzyme B(12) and methylcobalamin in water but acceptable when coenzyme B(12) and methylcobalamin are bound to serum or liver. Sulphitocobalamin in water is as active as cyanocobalamin and hydroxocobalamin but nitritocobalamin is less active. Factor B, the monocarboxylic acids of cyanocobalamin and hydroxocobalamin, and the dicarboxylic acid of cyanocobalamin in water were inactive.
水中的辅酶B12和甲钴胺在促进纤细裸藻Z株生长方面的活性低于相同浓度的氰钴胺和羟钴胺，而氰钴胺和羟钴胺的活性相同。然而，当与人类血清或人类肝脏匀浆结合时，这四种钴胺素的活性除了一个例外没有显著差异。结果表明，使用氰钴胺标准品的裸藻检测法不能令人满意地定量水中的辅酶B12和甲钴胺，但当辅酶B12和甲钴胺与血清或肝脏结合时是可以接受的。水中的亚硫酸钴胺与氰钴胺和羟钴胺活性相同，但亚硝酸钴胺活性较低。水中的因子B、氰钴胺和羟钴胺的单羧酸以及氰钴胺的二羧酸没有活性。
